A variety of articles incorporate straps or handles that assist with carrying the article. For example, a backpack generally incorporates a pair of straps that are configured to extend over both shoulders of an individual. Whereas the backpack often incorporates two straps, a messenger-style bag generally includes a single strap that extends over only one shoulder of the individual. Similarly, a golf bag conventionally includes either one strap or two straps that assist the individual with carrying golf equipment. Whereas straps extend over or contact a shoulder, handles are grasped by a hand and are often used on a piece of luggage, a briefcase, or a purse. Accordingly, different types of articles may incorporate a variety of shoulder strap configurations.
One consideration in the design of a strap or handle relates to comfort. In order to enhance the comfort of a strap or handle, compressible materials are often incorporated into areas that contact the individual, such as the shoulder or hand. With regard to straps, an advantage of compressible materials relates to decreased pressure concentrations on the shoulders of the individual, and particularly in areas of the shoulder that include the suprascapular nerve. When a strap extends over the shoulder, some areas of the shoulder experience greater loads than other areas of the shoulder, thereby forming pressure concentrations in the areas of greater loads. Compressible materials may be utilized, therefore, to distribute loads more evenly over a surface of the shoulder and decrease the pressure concentrations. Similar concepts apply to handles.
Examples of compressible materials suitable for straps and handles include polymer foams and fluid-filled bladders. U.S. Pat. No. 6,915,932 to Wolfe discloses a strap having a foam element and a fluid-filled bladder. The foam element defines various indentations, and the bladder is positioned within the indentations such that a combination of the foam element and the bladder provides cushioning when carrying an article. U.S. Pat. No. 6,223,959 to Chen discloses a strap for a golf bag, the strap having an envelope that encloses an air pocket formed of an inflated thermoplastic material. Similarly, U.S. Pat. Nos. 5,566,871 and 5,361,957 to Weintraub both disclose cushioning devices intended for use in a shoulder strap that incorporate an air-filled member.